Hydraulic Pumps

What is a hydraulic pump?

A type of positive displacement pumps used to pressurize fluid to do work by operating pistons in the hydraulic system. There are many different types, including gear pumps, vane pumps, screw pumps, piston pumps and plunger pumps. Although hydraulic pumps are among the simplest types of equipment, many can create extremely high pressure. This makes them useful in many commercial and industrial applications.

How do they work?

While each type operates according to unique principles, the basic idea is the same: the pump uses a direct application of force to a movable volume of liquid (in this case, hydraulic fluid), to squeeze the hydraulic fluid and pressurize it. Here is the general process.

  1. The hydraulic fluid is first drawn into the pump chamber by the moving gears, vanes, screws, pistons, or plungers in the pump.
  2. The moving parts then contract the pumping chamber to build up pressure as the hydraulic fluid moves through and exits the pump.
  3. The high pressure hydraulic fluid that exits the pump is then used to do work.

Hydraulic pumps often contain built-in pressure relief valves to protect the pump and the system in the event that a valve in the discharge piping is inadvertently closed. Sometimes the hydraulic system is further protected by an external relief valve.

Because the system is a closed system, the hydraulic fluid is generally clean, and makes an excellent lubricant. But, depending on the nature of the work, the hydraulic pumps must often produce several thousand psi of pressure, so they need to be robust enough to generate and safely maintain these high pressures.

Here are a few hydraulic pump manufacturers to consider.

Expert Advice

Dr. Lev Nelik recommends some valuable steps you can take to extend the life of your pump and ensure its operating under optimum conditions.

Learn how following the simple rule of NPSH Available > NPSH Required, can help you avoid cavitation.

Article explores some of the key principles behind positive displacement pumps and what makes them different from centrifugal pumps.

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Industry Updates

Switch to: Expert Advice | Pump Tweets

FoamPro has just announced its TurboStream® high pressure foam system. The TurboStream is compact and self-contained and produces high energy firefighting power.

Colfax Fluid Handling has created an online energy savings calculator for oil and gas industry pump applications, World Pumps reports. The calculator allows comparisons between centrifugal pumps and rotary positive displacement pumps in single and multiple pump applications.

In a move that combines two of the biggest players in water and fluid products systems, Pentair recently announced that it’s combining its operations with Tyco's flow control business. The Associated Press reported that the deal is worth about $4.53 billion.

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Pump Tweets

Here's a great read in The Atlantic highlighting the importance of water pumps -- and the man who repairs them -- to a small Kenyan village. In a farm town as small as Kikuyu, you're in serious trouble if the motor on your water pump breaks down, the writer reports. "Crops wither and die quickly in the sweltering heat. New motors are expensive, and out of the price range of subsistence farmers."

According to a company press release, Jeff Wiemelt will assume the role of president for the Sundyne on January 1, 2012. Wiemelt previously held vice president and general manger of Sundyne Americas and Sundyne Dijon in France.

KSB introduces immersion variant of high-pressure pump. The new pump, called Movitec VCl, is a vertical, multistage centrifugal pump that can be used for handling coolants, condensate and lubricants for machine tools. The pump has a max flow rate of 27 m3/hr and the maximum discharge head is 250 m.

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